1. Field of the Invention
The present invention relates to a locomotion device for sport or leisure intended to be used for moving over ground, preferably sloping ground.
2. Description of the Related Art
In the domain of winter sports, it is known to use a snowboard for moving over a snow-covered slope, the user guiding the board by the positioning of his/her body above the board, this inducing variations of the centre of gravity of the assembly formed by the surfer and the board. In practice, the use of a snowboard is limited to the winter season in the majority of regions.
Furthermore, it is known, for example by WO-A-99/48750, to produce a locomotion device which comprises an elongated chassis on which is mounted a pivoting sub-assembly for steering adapted to be manoeuvred by a seated user with his feet. The sensation of piloting is similar to that felt with a go-kart.
Other devices such as summer sledges are controlled like a skate board, i.e. by inclining a chassis on which the user places his feet with respect to an axis of a steering axle. The sensation of piloting is close to that obtained with a skate board.
The invention aims at proposing a novel locomotion device structure which makes it possible to feel new sensations of piloting, including over ground not covered with snow, these sensations of piloting being closer to those usually obtained with a snowboard.
In this spirit, the invention relates to a locomotion device for sport or leisure comprising a chassis adapted to accommodate at least one user and resting on the ground via engaging members, of the wheel or runner type, at least one of these members being mounted on a steering column articulated, with respect to the chassis, about an axis of rotation. This device is characterized in that it comprises a frame kinematically connected to the steering column, mobile with respect to the chassis and adapted to come into contact with the ground, this frame making it possible, by its movements with respect to the chassis, during abutments on the ground, to control rotation of the steering column about its axis.
Thanks to the invention, the frame capable of coming into abutment against the ground is used as the means for controlling the steering wheel or wheels or the or steering runner or runners. It therefore suffices for the user to incline the device in the direction of the ground for the frame to interact with the ground and consequently control the rotation of the steering column. Abutment of the frame on the ground may be obtained by the user modifying the position of his centre of gravity with respect to the device, similarly to that used with a snowboard. Change of direction is obtained by modifying the inclination of the chassis with respect to the frame. When the latter is in contact with the ground, the degree of inclination of the chassis may be modified by the user with his feet, without necessarily offsetting his centre of gravity, which makes it possible to vary the radius of curvature of the trajectory of the device.
According to advantageous but non-obligatory aspects of the invention, the locomotion device incorporates one or more of the following characteristics:
It comprises a single ground-engaging member disposed at one end, front or rear, of the chassis and a single ground-engaging member disposed at the other end, rear or front, of the chassis. In that case, each ground-engaging member may be provided to be mounted on a steering column articulated with respect to the chassis and kinematically connected to the frame, the frame being adapted to control rotation of each steering column about its own axis of rotation.
The axis of rotation of the steering column is inclined with respect to the vertical when the device rests on horizontal ground. This inclination of the steering column corresponds to the notion of steering error angle which may be defined over a cycle and the non-zero nature of the steering error angle of the steering column improves the stability of the device. However, this non-zero nature is optional.
Means are provided for returning the frame towards a position with respect to the chassis such that the ground-engaging member mounted on the steering column is oriented so that the device can move substantially in a straight line. These return means allow the device to advance in a straight line by default. These return means may be provided to be elastic and with adjustable elasticity.
Means are provided for damping vibrations between the ground and a user in place on the chassis, these means comprising wheels having low-pressure pneumatic tyre or elastic tyre, at least one telescopic damping fork, shock absorbers integrated in the chassis and/or a chassis with elastic memory.
The steering column bears a catch extending in a substantially radial direction with respect to its axis of rotation, while the frame is fast with a fork adapted to interact with this catch in order to control rotation of the column about this axis.
The frame is articulated on the chassis about an axis substantially parallel to the direction of displacement of the device in a straight line.
The means for connection between the frame and the steering column, the geometry of the frame and/or the geometry of the chassis are adjustable, which makes it possible to modify the conditions of piloting of the device and the sensations experienced. This also allows the conditions of piloting to be adapted to the morphology and/or athletic ability of the user.
The frame may be substantially in the form of a closed loop. It may also be formed by two half-frames kinematically connected to a front steering column and to a rear steering column, respectively, of the device. According to another approach, the frame may be substantially in S or Z form, having its respective ends kinematically connected to a front steering column and to a rear steering column, respectively, of the device.
The frame is equipped with at least one removable runner provided to come into contact with the ground. Such a runner protects the frame from shocks and may be changed as a function of its wear. The frame may also be equipped with a removable device incorporating caster(s) or roller(s) performing the same function.
An elastic net is provided between the chassis and the frame.
The chassis comprises a cradle substantially in the form of a loop and covered with a board adapted to support a user. According to another approach, the chassis comprises a cradle formed by two half-cradles each fast with a steering column and connected by a tie-piece. In that case, these half-cradles are advantageously articulated with respect to the tie-piece, with possibility of limited rotation, which makes it possible to dampen the shocks and/or vibrations. These two half-chassis may also be covered with a board adapted to support a user.
In the case or a supporting board being used, damping means may be arranged between the cradle and this board.
The means for connection between the frame and the steering column include means for returning the frame towards a position with respect to the chassis such that the ground-engaging member mounted on the steering column is oriented so that the device can move substantially in a straight line.
According to a first form of embodiment, the connection means comprise an element made of supple plastics material forming a sleeve adapted to surround an arm for controlling the steering column in rotation, this element forming at least one housing for receiving part of the frame.
According to another form of embodiment, an elastic member is adapted to slide on an arm controlling the steering column in rotation, this elastic member being fast with an element connected to a shank of the steering column. In that case, a fork fast with the element connected to the shank may be provided, adapted to alternately compress the elastic member against the arm controlling the steering column.
According to another form of embodiment, the connection means comprise a member articulated on an arm controlling the steering column and forming a fork adapted to cooperate with a shaft fixed with respect to the shank of the column.
According to another form of embodiment, the connection means comprise an elastically deformable endpiece, mounted on an arm controlling the steering column and connected to the frame by connecting rods or cables.
Means are provided for compensating the necessary clearance between the frame and the chassis in order to allow deformations of the cradle of this chassis. In that case, these compensation means advantageously include a compression spring disposed inside a sleeve fast with the frame, this spring surrounding a pin and exerting on part of it a clearance-compensating force.